Re: [Histonet] Paraplast Plus

From:Gayle Callis

We had trouble with this paraffin in the past:

Several things:

Although the droplet appear not miscible, have you tried stirring the 
paraffin after melting to redistribute the plastic polymer additives, etc 
that are in the paraffin.  This should be done before embedding, and before 
adding any melted paraffin to processor paraffin containers, pots.  During 
processing, agitaion should keep these resuspended.  Stirring paraffin 
before embedding EACH DAY is advisable to keep additives (heavier so they 
settle to bottom of paraffin pots) suspended or you will run into 
sectioning problems.  A plastic spatula is very handy for this purpose.

If stock paraffin is stored in a cold place and then melted, 
water  condenses and  water droplets form in bottom of paraffin 
pots/storage containers.  Store your stock paraffin at recommended 
tempertures, cool, but not extremely cold place, dry.  We found room 
temperature storage was adequate prior to melting.

Also, do not melt Paraplast Plus over 62C, high temperatures create havoc 
with this paraffin, and you may damage additives - we never exceeded 62C 
for melting, storage or processing protocols.

Poor sectioning occured with high temperature melting of this paraffin and 
also not stirring it before embedding or dispensing into paraffin processor 

Clean storage pots and embedding centers frequently.

and At 08:21 AM 3/9/2005, you wrote:
>We are using Paraplast Plus from Kendall (Tyco/Healthcare).  We have noticed
>that after the paraffin melts (in embedding center and paraffin pot) that
>there is what appears to be a straw colored liquid that is deposited at the
>bottom of the units.  It would appear that the liquid is not miscible with
>the melted paraffin. This liquid is causing problems with embedding.  Does
>anybody know where this liquid is coming from?

Gayle Callis
Research Histopathology Supervisor
Veterinary Molecular Biology
Montana State University - Bozeman
PO Box 173610
Bozeman MT 59717-3610
406 994-6367 (lab with voice mail)
406 994-4303 (FAX)

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